416 BOTANICAL GAZETTE [MAY 
ammonium chloride, potassium di-hydrogen phosphate, and magnesium 
sulphate had been added. The effect of the acid in combination with the 
different substances was estimated by the relative development of the cultures. 
It is noted that the antitoxic action of the substances examined is correlated 
with the ease with which they combine with the acid, as shown by conductivity 
-changes of the mixtures. Those which combine most readily with boracic 
acid are also most effective as antidotes to the toxic action of the acid. The 
antagonistic action of these substances, therefore, is attributed to their power 
of holding the acid in combination 
Studies of a similar nature ine been made by KuNKEL,” who investi- 
galactose, which are frequent constituents of culture media. These substances 
all modify the toxicity of salts, but not to the same extent nor in the same order. 
The author believes that this modification of toxicity may in part be the result 
of reactions between the salts and the organic substances of the medium,” 
but there appears to be no constant ieee saoicechidse reduction in the con- 
centration of ions caused by the add d the toxicity 
of the medium. On this account the author believes that the food substances 
themselves have an influence on the organism by which it is enabled to endure 
higher concentrations of poisons. This conclusion could hold good only in cases 
where the toxic effect was entirely due to the ionized portion of the molecule, 
otherwise there would be no reason for the expectation of a relation between 
ionic concentration and toxicity. The author finds that spores are capable 
of remaining alive a long time, two weeks or more, in the presence of toxic 
substances, provided the concentration is below that at which plasmolysis 
This hypothesis, it will be remembered, was suggested long ago by LIvINGSTON,” 
who observed a similarity between the action of salts on the cells of the alga 
Stigeoclonium and the withdrawal of water from the cells. In conclusion, the 
author points out, with justice, that the composition of the medium should be 
taken into consideration in studies on toxicity of substances to plants. 
t0 KUNKEL, L. O., The influence of search peptone, and sugars on the toxicity of 
various nitrates to Monilia sitophila (Mont.) Sacc. Bull. Torr. Bot. Club 40:625-630- 
1913. 
—, ical and chemical factors influencing the toxicity of inorganic salts 
to Monilia uke (Mont.) Sacc. Ibid. 41:265-293. 1914. 
= See foregoing review. 
Saeco B. E., Chemical stimulation of a green alga. Bull. Torr. Bot. 
Club 32:1-34. 1905. 
